Compositional, Functional and Rheological Characterisation of Peanut Oils Influenced by Ozonation, Roasting and Combination Process

As peanuts are prone to fungal attack, techniques like ozonation and heat treatment hold enormous potential. Peanut oil, being health-healthy, was extracted from O1: control, O2: roasted (166 degrees C for 7 min), O3: ozonated (6 mg L-1 for 30 min), and O4: ozonated + roasted peanuts and analysed for chemical, colour, phenolic, fatty acids and rheological properties. Roasting significantly affected peroxide, iodine, acid, p-anisidine values and stability of oils as compared to other treatments. The results indicated a decline in colour attributes of all oils except hue angle which were strongly correlated to increased levels of functional compounds expressed by third-degree polynomial. O4 oil indicated best quality in terms of high atherogenic, thrombogenic, calculated oxidisability value and low hypocholesterolaemic: hypercholesterolaemic indices of fatty acid. Oils exhibited pseudoplasticity postulated by Ostwald-de Waele and Herschel-Bulkley models. Arrhenius equation and oscillatory rheology predicted temperature dependency and crystal matrix behaviour. Overall, the O4 oils followed by O3 from ozonated peanuts individually and along with roasting are pivotal to cater the rising demands of oils due to their better appearance, fatty acids and rheology. The stability of oil remained unaffected by ozonation; however, a decrease was observed in colour attributes, except for the hue angle. A third-degree polynomial indicated a correlation between bioactives and colour. The oil obtained from combined treated peanuts exhibited the lowest values for AI, TI and COX indices, while showing the highest HH index. The oils demonstrated pseudoplastic behaviour, and oscillatory rheology suggested the predominance of the viscous element in the crystal matrix. image